Discovery of a novel and a rare Kristen rat sarcoma viral oncogene homolog (KRAS) gene mutation in colorectal cancer patients

Figures & data

Table 1. Nucleotides and amino acid changes in KRAS gene in CRC patients

S. No	No. of patients	Nucleotide change	Protein change	Reported or Novel
Codon 12
1	1	c. 34 G>T	p. Gly12Cys	Reported
2	2	c. 34 G>C	p. Gly12Arg	Reported
3	2	c. 35 G>C	p. Gly12Ala	Reported
4	5	c. 35 G>T	p. Gly12Val	Reported
5	6	c. 35 G>A	p. Gly12Asp	Reported
Codon 13
6	1	c. 37 G>T	p. Gly13Cys	Reported
7	2	c. 38 G>A	p. Gly13Asp	Reported
Codon 17
8	4	c. 51 T>A	p. Ser17Arg	Novel (this study)
Codon 31
9	3	c. 91 G>A	p. Glu31Lys	Reported in only 1 patient (ultra-rare)

Figure 1. Chromatograms showing mutations in KRAS gene in representative patients

Table 2. Characteristics of CRC patients with KRAS mutations

S. No	Sample ID	Mutation	Age	Gender	Tumor Location	Preoperative CEA	Postoperative CEA	Surgery	Response to Treatment*
1	CR-576	p. G12C	55	Female	Right	50	0.3	2	1
2	CR-2090	p. G12R	60	Male	Left	5.2	0.32	2	2
3	CR-934	p. G12R	28	Female	Left	3.5	1.6	2	2
4	CR-4690	p. G12A	23	Female	Left	4.2	0.2	2	3
5	CR-4688	p. G12A	23	Female	Right	3.4	0.4	1	1
6	CR-926	p. G12V	65	Female	Right	6.6	1.13	1	1
7	CR-104	p. G12V	51	Male	Left	20.5	2.51	2	1
8	CR-196	p. G12V	62	Male	Left	8.9	2.7	2	2
9	CR-1039	p. G12V	58	Male	Right	13.42	0.7	3	2
10	CR-220	p. G12V	42	Female	Left	9.8	3.8	2	2
11	CR-5771	p. G12D	47	Male	Left	6.9	1.7	1	1
12	CR-218	p. G12D	70	Female	Right	2.4	0.2	2	2
13	CR-384	p. G12D	82	Male	Rectal	12.5	5	2	1
14	CR-230	p. G12D	63	Male	Left	45	130	3	3
15	CR-234	p. G12D	57	Female	Rectal	1.4	0.6	1	1
16	CR-477	p. G12D	45	Male	Right	14.8	10.7	2	2
17	CR-1080	p. G13C	59	Male	Left	11.61	1.4	2	3
18	CR-72	p. G13D	31	Female	Right	1.99	2.07	2	1
19	CR-117	p. G13D	52	Female	Left	127	5.5	2	2
20	CR-692	p. S17R	66	Male	Right	10.6	1.9	1	2
21	CR-106	p. S17R	54	Male	Left	1.26	0.5	2	1
22	CR-163	p. S17R	75	Female	Left	127	5.5	2	2
23	CR-210	p. S17R	50	Male	Rectal	10.6	1.9	2	2
24	CR-961	p. E31K	65	Female	Right	2.8	3.2	2	2
25	CR-601	p. E31K	35	Male	Left	14.4	0.9	1	1
26	CR-181	p. E31K	73	Male	Right	6.05	2.52	2	2

*(1 = Complete response, 2 = Partial response, 3 = No response)

Figure 2. KRAS homology model of wild and mutated proteins. KRAS model was build using Swiss Model automated homology modeling platform based on the FASTA sequence downloaded from the UniProt Knowledgebase: (a) KRAS homology model of wild type (WT) protein showing the Ser at the 17^th position (b) KRAS homology model of the novel missense mutation identified in our study showing the substitution of Ser with Arg at the 17^th position

Figure 3. Ramachandran Plots for KRAS Homology Model (Wild Type). The Ramachandran plots of the KRAS homology model showed that 93.22% of residues were in the favored region, 2.26% were in the outlier region, rotamer outliers were 3.80%, C-beta deviations were 4, bad bonds were 0 out of 1453, bad angles were 34 out of 1951 and Cis Non-Proline 2/174